Field of the Disclosure
The present disclosure relates in general to semiconductor memories, and more specifically to coherent memory interleaving with uniform latency.
Description of the Related Art
Memory interleaving refers to distributing accesses made by programs uniformly across multiple available memory devices in order to achieve higher memory throughput while still maintaining lower latencies by attempting to hide delays between consecutive accesses to a single device. Ultimately, memory interleaving improves the performance of applications running in the system and relieves programs of the worry about optimizing data placement in memories.
The effectiveness of interleaving depends on whether accesses to different memory devices have the same or similar latency. If there is significant basic inequality between their access times, then the intended benefit is lost. In that case one might just as well just access the device with the lowest native latency.
Many connectivity topologies for large computer systems inherently present large inequality of path-lengths to different memory devices connected within them. The differences in latency makes access times non-uniform, which undermines the usefulness of interleaving.